Many mobile devices are capable of connecting to Wireless Access Points (WAPs) to transmit and receive data. Before connecting to a WAP, a mobile device may conduct a search to discover WAPs within range of the mobile device. Conventional methods for discovering WAPs include passive scanning and active scanning.
In passive scanning (also known as beacon scanning), a mobile device may dwell on each channel of a Wireless Local Area Network (WLAN) and wait to receive a beacon from a WAP on each channel. The mobile device may dwell on each channel for a time between a minimum and maximum limit. In active scanning (also known as probe scanning), the mobile device may broadcast a single probe request (e.g., on a given channel) and wait for a response from WAPs within range of the mobile device.
In a typical WAP discovery process using passive or active scanning, the mobile device may spend a good portion of its power transmitting probe requests to, or listening for beacons or responses from, WAPs that either are nonexistent or do not ultimately establish a connection with the mobile device. Because the radio resources used to transmit and receive wireless communications may consume a significant amount of power, searching for WLAN access points using these conventional methods may be power inefficient and may shorten the usable battery life of the mobile device.